1.3: Studying LIFE

• VOCABULARY:– Biology– DNA– Stimulus – Sexual reproduction– Asexual reproduction– Metabolism– Homeostasis– Biosphere– Evolve

What are some characteristics of living things? What does it mean to be “ALIVE”?

1) Living things are ORGANIZED.

1) Living things are ORGANIZED.

• Made up of cells

–UNICELLULAR: one celled

–MULTICELLULAR: many celled

2) Living things are based on a universal genetic code:

● ASEXUAL = one parent; cell division, cloning, budding, regeneration

3) Living things REPRODUCE.

● SEXUAL = two parents; sperm and egg

3) Living things REPRODUCE.

• Growth: increase in size & formation of new structures (could be at the cellular level)

• Development: cells increase in number and become different (differentiate)

• Heat

• Light

• Pressure

• Sound

• Gravity

Examples:

• A plant seed only germinates when there is sufficient water and temperature.

• Plant roots grow down.

• Plant leaves grow towards sunlight.

• HOMEOSTASIS: process by which organisms keep their internal conditions relatively stable–Example: How do humans maintain the

same body temperature?• too hot… we sweat• too cold… we shiver

7) Living things require ENERGY.

• All living things use energy: make their own energy or consume energy– PHOTOSYNTHESIS: using light energy to make

“food” energy– METABOLISM: combination of chemical

reactions through which an organism builds up or breaks down materials

Photosynthesis

Uses Metabolism

8) ADAPTATION & EVOLUTION

● ADAPTATION: any structure, behavior, or internal process that enables an organism to respond to stimuli and to better survive in a particular environment

8) ADAPTATION & EVOLUTION

● EVOLUTION: change over time–A group of organisms can change over

time–Even though an individual develops,

their inherited traits do not change

leg bone in a whale

Branches of Biology

• Diversity of life is so great,

biology is separated into branches– ZOOLOGY: study animals

– MICROBIOLOGY: study bacteria

– BOTANY: study plants

– ETHOLOGY: study animal behavior

– PALEONTOLOGY: study life from the past

Biosphere > Ecosystem > Community > Population >

Organism > Organ Systems > Organs > Group of Cells (Tissues)

> Cells > Molecules > Atoms > Protons, Neutrons, Electrons

How do we study living organisms?

• Key Concepts:– What measurement

system do most scientists use?

– How are light microscopes and electron microscopes similar? How are they different?

• Vocabulary:– Metric system– Microscope– Compound light

microscope– Electron microscope– Cell culture– Cell fractionation

Metric System• Length:

– Meters

• Mass:– Grams

• Volume:– Liters

• Temperature:– ºCelsius

kilo hecto deka (g, m, or L)

deci centi milli

.001 .01 .1 1 10 100 1000

SCALE = multiples of 10

Analyzing Biological Data The simple way to record data

● Make a table…

● Then make a graph– Graphs make patterns

easier to recognize

and understand

GRAPH = visual representation of data

1) DESCRIPTIVE title

2) x and y axis labeled

3) units for both the x and y axis

4) scale is evenly and correctly spaced for data

5) legend / key when appropriate

Organizing DataData is organized and presented in tables, charts, and graphs.

LINE GRAPH: best for displaying data that CHANGE.– Independent Variable: x-axis– Dependent Variable: y-axis

Temperature Increase of a Beaker of Water

250

300

350

400

450

0 50 100 150 200 250 300 350 400

Time (sec)

Tem

pera

ture

(K)

BAR GRAPH: useful when you want to compare data for several individual items

Leading Causes of Death in 2000

300

233

107 9857

0

50

100

150

200

250

300

350

HeartDisease

Cancer Diabetes Accidents HomicideNu

mb

er

of

De

ath

's p

er

100,

000

Pe

op

le

MICROSCOPES!

• Light Microscopes

• Electron Microscopes

MICROSCOPESCOMPOUND LIGHT MICROSCOPE: most

common scope• Advantages: get higher magnification

than with a dissecting scope.• Drawbacks: the light comes from below

so sample must be very thin so you can see – Useful for viewing single cells– Usually view dead things with this

microscope.• Limit of resolution: if you magnify beyond

this point, the object will be blurry.

EYEPIECE

LOW-POWER OBJECTIVE

HIGH-POWER OBJECTIVE

STAGESTAGECLIPS

STAGECLIPSBASE

MIRRORLAMP

IRIS

DIAPHRAGMCOURSE ADJUSTMENT

FIN

E

AD

JUS

TM

EN

T

ARM

COURSE ADJUSTMENT

FINE ADJUSTMENT

ARM

DISSECTING MICROSCOPE: used to view dissection or small live (sleeping) animals such as fruit flies.

• Advantages: can view samples that are alive; large field of view

• Drawbacks: magnification is not as high as other microscopes.

SCANNING ELECTRON MICROSCOPE (SEM): used to see very small “stuff”

• Advantages: can study very small objects such as viruses and individual molecules; limit of resolution is 1000x that of a light microscope.

• Drawbacks: done in a vacuum, so object must be dead; also very expensive!

PINHEAD

Face of an ant!

Laboratory Techniques

● Cell Culture:

-a group of cells develops from a single original cell.

● Cell fractionation & Centrifugation:

-used to separate the different parts of a cell1) Cells are blended

2) Added to a liquid and placed in a tube

3) Centrifuge at 20,000 revolutions per minute

4) Spinning separates the cell parts by density.

In comparing differences in sea level from decade to decade, a scientist

should use what type of graph?

a) Bar graph

b) Pie Chart

c) Line graph

On that graph, what would be on the x-axis? On the y-axis?

X-axis = time in decades

Y-axis = sea level in kilometers

Welcome to BIOLOGY!